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Speaker 1: stuff works dot com where smart happens. Hi'm Marshall Brain
Speaker 1: with today's question. What makes Nascar engines different from street
Speaker 1: car engines. It's pretty obvious that Nascar engines and street
Speaker 1: car engines are different. For example, a typical Nascar engine
Speaker 1: has something like seven horsepower, and you just don't normally
Speaker 1: see that in a street car engine. But the fact
Speaker 1: is that at the bottom, you know, at the very beginning,
Speaker 1: these two types of engines start out in a very
Speaker 1: similar way. A team starts building a Nascar engine with
Speaker 1: a block and a cylinder head that's remarkably similar to
Speaker 1: a street version of the same thing. For example, if
Speaker 1: a team is building a Dodge engine, they would start
Speaker 1: out with a block based on a three forty cubic
Speaker 1: inch V eight engine design that was produced in the
Speaker 1: nineteen sixties. The actual engine blocks and heads are not
Speaker 1: made from the original tooling. They're actually custom made race
Speaker 1: engine blocks, But they have some things in common with
Speaker 1: the original engines. For example, they have the same cylinder bore,
Speaker 1: center lines, the same number of cylinders, and the same
Speaker 1: based displacement, And like the original nineteen sixties engines, the
Speaker 1: valves are driven by push rods rather than by overhead camshafts.
Speaker 1: But NASCAR engines do produce seven fifty horsepower, and they
Speaker 1: do that without turbochargers, superchargers, or any particularly exotic components.
Speaker 1: So how do they make all that power? Here are
Speaker 1: some of the things that distinguish a NASCAR engine from
Speaker 1: a regular engine. First, there's the displacement three cubic inches
Speaker 1: or five point eight seven leaders. Not many cars have
Speaker 1: engines this big anymore, but the ones that do usually
Speaker 1: only generate about three hundred horsepower, so there's something else
Speaker 1: besides displacement that's doing it. Second, the NASCAR engines have
Speaker 1: extremely radical cam profiles, which open the intake valves much
Speaker 1: earlier and keep them open longer than a street car
Speaker 1: engine would. This allows more air to be packed into
Speaker 1: the cylinders, especially at high speeds. Third, NASCAR engines use
Speaker 1: massive carburetors that let in huge volumes of air and fuel.
Speaker 1: There are no fuel injectors on these engines. Fourth, they
Speaker 1: have extremely high intensity programmable ignition systems, so the spark
Speaker 1: timing can be customized to provide the most possible power. Five.
Speaker 1: All the subsystems like cooling pumps, oil pumps, steering pumps,
Speaker 1: and alternators are designed to run at sustained high speeds
Speaker 1: and temperatures, so the engine is gonna be able to
Speaker 1: last through the race. Finally, when a NASCAR engine is assembled,
Speaker 1: it's built to very exacting tolerances. The parts of machine
Speaker 1: much more accurately than normal so that everything fits perfectly.
Speaker 1: Cylinders are board to more exacting tolerances than street cars.
Speaker 1: The crank chefts and other rotating parts are balanced. Making
Speaker 1: sure that the parts are as close to their exact
Speaker 1: dimensions as possible helps the engine achieve its maximum potential
Speaker 1: power and also helps reduce wear. If the parts are
Speaker 1: too big or too small, power can be lost due
Speaker 1: to extra friction or pressure leakage through bigger than necessary gaps.
Speaker 1: After the engine is assembled, it runs on a dynamometer
Speaker 1: for thirty minutes to break it in. The engine is
Speaker 1: then inspected, The filters are checked or excess metal filings
Speaker 1: and any other signs of excessive wear. If it passes
Speaker 1: this test, then it goes on the dynamometer for another
Speaker 1: two hours. During this test, the ignition typing is dialed
Speaker 1: in to maximize the power that the engine produces, and
Speaker 1: the engine is cycled through various speed and power ranges.
Speaker 1: After this test, the engine is again disassembled and inspected thoroughly.
Speaker 1: The valve train is pulled and the camshaft and lifters
Speaker 1: are expected. The insides of the cylinders are examined with
Speaker 1: Boris scopes. The cylinders are pressurized and the rate of
Speaker 1: leakdown is measured to see how well the pistons and
Speaker 1: seals hold the pressure. All the lines and hoses are checked.
Speaker 1: Only after all these tests and inspections are finished, is
Speaker 1: the engine ready to go to the races. Ensuring the
Speaker 1: reliability of the engine is critical. Almost any engine failure
Speaker 1: during a race eliminates any chances of winning for moral
Speaker 1: This and thousands of other topics at how staff works
Speaker 1: dot com. Streaming TV shows and movies directly to your
Speaker 1: home is a breeze With Netflix. As a Netflix member,
Speaker 1: you can instantly watch TV and movies on your PC, mac,
Speaker 1: mobile device, or right on your television. Get a free
Speaker 1: thirty day trial membership. Go to Netflix dot com slash
Speaker 1: brain stuff and sign up today.